pcIRT

The R package pcIRT provides functions that estimate the following IRT models:

• Multidimensional Polytomous Rasch model (MPRM) (Rasch, 1961)

MPRM is a multidimensional IRT model for multicategorical data. For each response category, a latent dimension is assumed. The item characteristic curves of an example looks like this:

• Continuous Rating Scale model (CRSM) (Müller, 1987)

CRSM is an extension of the Rating Scale model. It can be used to analyze items with a visual analogue scale for example.

• Dichotomous Logistic Rasch model (Rasch, 1960)

By defining the design matrix, restricted Rasch models (e.g. the Linear Logistic Rasch model) can be estimated, too.